While foals are on their feet and mobile within hours of birth, gait and balance mature and stabilize over time. To learn more about the dynamic changes the hoof undergoes in the first six months, a team of Dutch researchers recorded pressure plate measurements at walk and trot from 10 Dutch Warmblood foals in their first 24 weeks.
The team measured toe-heel and medial-lateral (inside to outside) hoof balance asymmetry, as well as preferred landing strategy of the front and hind limbs.
“The results of this study showed that the dynamic hoof balance changes during early life in foals,” said Ben Gorissen, DVM, PhD, who conducted this research while a PhD candidate at Utrecht University’s Faculty of Veterinary Medicine and is now a lecturer at Aeres MBO Almere, both in The Netherlands.
“These alterations in hoof balance seem to follow the conformational changes reported and observed in young foals,” he said. “The toe-heel balance gradually shifts to the heel and the medio-lateral balance to lateral. This is accompanied by a gradual shift of landing preference in the same directions.”
Hoof dynamics, he said, display significant changes in the first half year of life: “A substantial decrease in the variability of (part of) the loading pattern over time was observed, which is also seen in static balance development in young foals. Most prominent changes were observed in the medial-lateral hoof balance of the hind limbs in the second part of the stance phase.”
During the first weeks of life, the team observed a significant reduction in variability, he said, “which is in line with the fast initial improvement of static balance and the significant reduction in variability of the stance duration observed in young foals. It is likely due to better control thanks to the maturation of the neuromuscular system.”
Subtle limb deviations are common in very young foals, with carpal (knee) and fetlock valgus (outward) deviations (toeing out) being most prevalent, Groissen said.
“Newborn foals also tend to splay their limbs to compensate for poor balance and muscle tone,” he said. “Such mild deviations in conformation, which were also present in the foals in this study, might help to explain the relatively higher loading of the medial part of the hooves during the first weeks of life. Further, the hind limbs showed relatively more loading of the heel region of the hooves compared to the front limbs, which could be related to a mild degree of digital hyperextension (weak tendon), as is commonly seen in newborn foals and which is more prominent in the hind limbs.”
In addition, the team collected hock and stifle radiographs at 4–6 weeks and after 6 months monitored for osteochondrosis (OC).
“Osteochondrosis was not a significant factor in our model, while there was a small, yet significant effect of OC on kinetic parameters in our previous study,” Gorissen said. “This suggests that the primary component of compensation of pain (i.e. lameness) is the even unloading of the lame limb and that ground reaction forces are more accurate in detecting low degree lameness than pressure patterns.”
Data in this study is limited by the small sample of 10 foals of the same breed (Dutch Warmblood) bred for the same discipline (show jumping) at a single stud farm. In addition to a larger sample, long-term data could also prove useful.
“It would be interesting to follow gait development for a longer period of time to see the complete development of gait (parameters) from foal to sport horse,” Gorissen said. “The period when the horse starts carrying a rider would be interesting to follow in order to see whether the development of balance when ridden is comparable with the development of balance during early life.”
His main takeaway from this study’s results? “Knowledge of the development of dynamic hoof balance can be helpful in determining normal and abnormal gait,” he said. “Furthermore, this information may be useful for the clinician when making decisions about hoof trimming in early life.”
This study, “The development of hoof balance and landing preference in the post-natal period,” was published in Equine Veterinary Journal.